from collections import deque


def iks(a, b, c):
    return a != c and ((a < b > c) or (a > b < c))


def main():
    W, H = map(int, input().split())
    M = [list(map(int, input().split())) for i in range(H)]
    Q = deque([(i, 0, 0) for i in range(1, 11)])
    D = [[[None]*W for i in range(H)] for j in range(1, 11)]
    for i in range(1, 11):
        D[i][0][0] = 0
    while len(Q) > 0:
        b, x, y = Q.popleft()
        if (x, y) == (H-1, W-1):
            print(D[b][x][y])
            return
        for dx, dy in [(-1, 0), (1, 0), (0, 1), (0, -1)]:
            bv, r, c = M[x][y], x + dx, y + dy
            if 0 <= r < H and 0 <= c < W and D[bv][r][c] is None and iks(b, M[x][y], M[r][c]):
                D[bv][r][c] = D[b][x][y] + 1
                Q.append((bv, r, c))
    print(-1)
    return


if __name__ == '__main__':
    main()